The increased bandwidth introduced by the penetration of broadband and the availability of enhanced terminal capabilities, content creation and publishing tools has significantly increased in availability on the Internet of user generated content, e.g. YouTube, Podcasting, etc. Content aggregators such as Joost, BBC iPlayer are also becoming established sources of legal online content.
Peer-to-peer technology has shown itself as a viable technology for distributing user generated content and technology of choice of the content aggregators. For example, the iPlayer utilizes an IMP P2P client. Often referred to simply as peer-to-peer, or abbreviated P2P, peer-to-peer architecture is a type of network in which each workstation has equivalent capabilities and responsibilities. This differs from client/server architectures where some computers are dedicated to serving the others. The P2P network distributes the computing power between connected peers in the network and utilizes the aggregated resources, e.g. network available bandwidth, for efficient content distribution. P2P is often used as a term to describe one user linking with another user to transfer information and files through the use of a common P2P client to download material, such as software upgrades or media files.
When downloading content using P2P clients, pieces or chunks of the selected file are gathered from several nodes simultaneously in order to decrease download time and to increase robustness of the P2P network. The set of peers to download data chunks from has been selected by a so called Tracker which functions as a gateway between peers in the P2P network. It gathers information on which peers have what data chunks and spread that information to any requesting peer. The tracker can be located anywhere on the network.
A recent trend in the Internet is the use of P2P technology to build content distribution networks. Examples of commercial systems include Velocix from CacheLogic and Gridcasting from GridNetworks. Based on recent trends like those in the UK with BBC's IP player, an assumption is that P2P technology will be used by content providers in the near future as a cheap way to distribute content. At some point network operators themselves may turn to using P2P for content distribution, in particular video distribution. In any case the operators would first need to manage the P2P traffic in their networks. For traffic of over-the-top P2P applications, the operator would like to keep the peering traffic low as well as improving the end-user experience. This requires techniques and mechanisms that are operator specific to complement the already existing Internet-based methods.
In P2P systems based on Tracker architecture when a client requests content, it contacts the Tracker in order to obtain addresses of peers having the desired data chunks. The Tracker replies with a so called tracker response to the client which contains a list of addresses to peers having the data. For example, in the BitTorrent protocol the list of peers in the tracker response is by default 50, if the number of available peers is equal or above 50. If there are more peers that have the desired chunk of content, the tracker randomly selects peers to include in the response, or the tracker may choose to implement a more intelligent mechanism for peer selection when responding to a request. This selection can for example be made based on locality, network measurements and similar. All based on the viewpoint of the Tracker.
The problem is that much locality information and other operator specific information is not usually available to a central Internet based Tracker. Further, the Tracker may not always take the operator needs into account—such as keeping traffic local to the operator at hand. The same type of problem appears if the P2P system is based on Distributed Hash Table DHT-like algorithms.